U.S. Pat. No. 8,226,580 describes a method for operating a medical probe. The method includes pressing a distal end of the medical probe, which includes one or more arms that extend diagonally outward from a central shaft and have respective position transducers coupled thereto, against an intra-body surface, so as to cause the arms to exert pressure on the surface and bend with respect to the central shaft in response to the pressure. Positions of the respective position transducers coupled to the arms are measured, and the pressure exerted by the arms is estimated responsively to the measured positions.
U.S. Pat. No. 8,478,379 describes a method for visualization. The method includes receiving an input indicative of respective apparent coordinates of a plurality of points disposed along a length of a probe inside a body of a subject, and applying a model of known mechanical properties of the probe to the apparent coordinates so as to compute a cost function with respect to shapes that can be assumed by the probe in the body.
A shape is chosen responsively to the cost function, and corrected coordinates of the points along the length of the probe are generated based on the shape. The representation of the probe using the corrected coordinates is then displayed.